XML documents are being increasingly stored and managed within content repositories. These content repositories are typically based on a database system and offer file system abstractions such as foldering, access control, versioning and protocol access.
The size of the individual XML documents has also been growing. XML documents can be as large as multi-megabytes and are expected to grow significantly over time.
For large documents, it may be desirable to apply different access control policies for different parts of the document. For example, in the case of a XML document representing a book, the editor may have write access on the entire book whereas individual writers can only update their assigned chapters. However, since access control in a repository may only be provided at the document level, it is difficult to provide access control level of a granularity lower than the document level.
Similar issues with granularity afflict other repository functions. With respect to versioning, only an entire document, rather than a portion thereof, may need to be versioned. When only a small part of a document changes to create a new version of the document, an entire new version of the document is created. Similarly, when updating a small portion of a large document, the entire document is overwritten.
Clearly, there is need for a mechanism that addresses these problems.
The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.